It is proposed to design, construct, test, and systematically refine a state-of-the-art Fourier transform ion cyclotron resonance mass spectrometer built around a 9.4 tesla superconducting magnet. The instrument will optimized for unsurpassed sensitivity, mass resolution, and mass accuracy for singly- and multiply- charged macromolecular ions up to 150,000 dalton. The instrument will incorporate the following features: electrospray, Cs+ liquid secondary ion, and matrix-assisted laser desorption ion sources; a novel ion transfer and trapping method; stored wave form dual-channel broadband dipolar and quadrupolar excitation; fast data acquisition and processing for wide mass range at high mass resolving power; and rf- linearized ion trap for increased upper mass limit, more accurate mass measurement, and more accurate ion relative abundances, higher- resolution MS/MS performance, increased dynamic range, and linearized detection. Theoretical numerical simulations will be used to determine the mechanism(s) for ion trapping and mass spectral line- broadening for high-mass ions (particularly singly-charged ions), including applied static and rf electric field, fully mapped magnetic field, and coulomb forces between ions. The results of those tests will guide the design of ion injection, ion trapping, and excitation/detection techniques designed to optimize high-mass ion analysis. Applications for these technical developments include identification, sequencing, and structural analysis of phospholipids, oligosaccharides, proteins, oligonucleotides, and complex unseparated mixtures.